lattice_vector           4.17970000        0.00000000        0.00000000
lattice_vector           0.00000000        4.17970000        0.00000000
lattice_vector           0.00000000        0.00000000        2.66690000
atom          0.000000        0.000000        0.000000  Si  
atom          0.306200        0.306200        0.000000  O